Dr. Sven van de Wetering is an Associate Professor of Psychology at the University of the Fraser Valley, Canada. His research interests are in “Conservation Psychology, lay conceptions of evil, relationships between personality variables and political attitudes.” In a 4-part interview series, we explore the philosophical foundations of psychology.
Scott Douglas Jacobsen: What philosophy best represents the opinion of most psychologists regarding the means by which human beings think, feel, and act?
Dr. Sven van de Wetering: I think we are still very far from a consensus on this issue. My personal take would be to still use the metaphor of the human as a computer. The gross outlines of the computer’s programming have been laid down by the process of evolution by natural selection, and the fine tuning done by various forms of learning. Feelings are part of the overall system, not some sort of exogenous factor.
These ideas are all at least several decades old, and to my mind, they work well together, but each component of the triad of information processing, evolution, and learning is rejected by some psychologists. Some psychologists find that thinking of cognition as information processing is unhelpful, others believe in information processing, but consider the human information processor so general in its functioning that evolutionary psychology has no heuristic value, and some are happy with the concept of the mind as an evolved computer, but think that learning processes only do some very minor tweaking around the edges, and are not really worth worrying about.
I guess what I am trying to say is that psychology is a fundamentally pluralistic enterprise. No single theory answers your question because the human mind is a very complex device that can be fruitfully described at many different levels and from many different points of view. Pluralism is an uncomfortable and cognitively demanding stance that is not for everyone, even among people with PhDs in psychology. Furthermore, even pluralists get things wrong (a lot), so one sometimes wonders what the payoff is. Other than psychology being fun, of course.
SJ: What is the worldview, and statistical outlook, that you try to inculcate in students?
Dr Sven van: As with several other aspects of psychology, I find that it has to be taught in two ways. One is at the level of the community standards of academic psychology. Certain statistical procedures need to be taught because academic psychologists expect one to know them, and one therefore needs to know them because it is expected, regardless of the intellectual merits of doing so.
The other is to do whatever it takes to find out what the data actually means. This often entails doing more descriptive work than what you see in many journal articles. In some really egregious examples, I have seen published articles where authors claimed their hypothesis was supported because some test said p<.05, but when I actually looked at the group means, the difference between them was in the opposite direction from the one predicted.
This is an extreme example, but something I see much more commonly is people writing things such as “Variable y induces people to produce behaviour x.” But when I look at the actual data, I find that both groups actually tended to avoid engaging in behaviour x, but members of the experimental group were slightly less likely to avoid behaviour x than members of the control group, and therefore people actually engaging in behaviour x made up a fairly small proportion of the overall sample.
Still more frequently and less egregiously, people will write about a difference in means as if everyone in every group was behaving in the exact way that the group mean indicates they are behaving. There is often little or no acknowledgment of variability in responses, even though the reported standard deviations indicate that this variability is substantial.
If I can summarize this paragraph, let me say that p values are given too much attention at the expense of descriptive statistics, and descriptive statistics are often being treated as if they describe everything, rather than being highly aggregated summaries that throw a lot of information away. It is of course right to summarize and to ignore individual cases in our research reports (because to do otherwise would invite cognitive overload), but we should try to avoid conventions in writing that make it seem like the individual cases don’t even exist or that the summary statistics contain all the information of interest.
Pluralism is an uncomfortable and cognitively demanding stance that is not for everyone, even among people with PhDs in psychology. Furthermore, even pluralists get things wrong (a lot), so one sometimes wonders what the payoff is.
We of course go into research with hypotheses in mind, but if we don’t spend many hours playing with the raw data, we don’t get to find out what the data are actually telling us. It’s always exciting when p<.05, but that’s always only a small part of the story. Playing around with the raw data, graphing them, noticing anomalies, etc. helps keep us alert to the complex messiness of human behaviour, and helps steer us away from unjustified formulations such as “variable x causes this change in variable y” when really all we know is that in one study, on average, variable x was associated with that change in variable y, and there is seldom evidence that variable x had that effect on variable y for every single person in the study, or even for a majority of people.
SJ: Between rigour and relevance, where has there been the most fruitful growth of real data about people?
Dr Sven van: I am very hesitant to pronounce on this, because I am more attuned to developments on the side that emphasises rigour. That being said, I think developments have not been entirely positive on my end of the playing field, given the replication crisis and all. It may be that things are even worse among those who emphasise social relevance, but my personal opinion is that no branch of psychology is in a great place right now.
SJ: Thank you for your time, Sven – always a pleasure.
Read Q & A of Session 1 with Dr Sven van de Wetering here
Read Q & A of Session 3 with Dr Sven van de Wetering here